Advances in electronic technology combined with lowering cost have enabled electronic devices to proliferate and become ubiquitous. In recent years, a trend toward convergence among electronic devices has emerged as users perceive synergy among these devices. However, the convergence path has not been without its wrinkles, especially for computers and televisions.
Computers and televisions are two popular electronic devices that have developed in separate industries. As a result, dissimilarities in the standards have emerged between the two industries. One difference that has made convergence between computers and televisions especially challenging is the different scanning techniques employed to display images.
Traditionally, computers have been designed to display computer-generated text and graphic images on computer monitors. Images generated by computers typically employ standards that utilize an under-scanning protocol. As discussed herein, under-scanning refers to the process of manipulating the image source to allow the full image (i.e., all pixels of the image including the outermost edges of the image) to be displayed. Therefore, images shown on computer monitors do not appear cropped or truncated.
In contrast, televisions typically employ standards that utilize the over-scanning protocol. As discussed herein, over-scanning refers to the process of cropping the image source to hide the outside vertical and horizontal edges of the image in order to avoid showing the black border around the image. One way to achieve over-scanning is by enlarging the original source image to exceed the size of the viewable portion of the television set. Accordingly, the outside edges are not displayed and are essentially “hidden” from the user's viewing.
Generally speaking, an image may be divided into three parts: the action safe zone (the outer five percentage of the image edge), the title safe zone (the outer ten percentage of the image edge, including the action safe zone), and the display zone (the percentage of the image that does not include the action/title safe zones). The extent of over-scanning that may occur in each television may vary depending upon the specific manufacturers. Manufacturers typically hide the action safe zone and usually expand the image to also hide the title safe zone. Thus, the display zone is usually the part of the image that is shown on the television set.
It is believed that over-scanning first developed when sharp fluctuations in electrical voltages would cause the image displayed on the earlier television models to “jiggle” (i.e., to move back and forth in an unsteady manner). To enhance the viewer's experience, a percentage of the outer edges of the image is hidden from the user's view; thus, the image that is displayed on the television set appears stable.
Consider the situation wherein, for example, a director of a movie has to make sure that actions that may be relevant to the story line are not accidentally cropped due to over-scanning. An image generated to be displayed specifically on television sets typically takes into account the over-scanning by the monitor that may occur. As a consequence, the image's creator tends to keep the relevant part of the image within the aforementioned display zone to ensure that the relevant part is not cropped when displayed on a television set.
In addition to the scanning protocol differences, the connectors that link computers to the monitors may also affect the way computer-generated text and graphic images are displayed. A computer-to-monitor connector may be a digital connector, e.g., video graphic array (VGA) connector or display video interface (DVI) connector, or an analog connector, e.g., composite connector, S-video connector, and component connector.
Digital connectors are bi-directional connectors that may have extended display identification data (EDID) capabilities. As discussed herein, the EDID capability refers to the ability of the monitor to furnish display-related data to the computer, and the computer's ability to receive and use such display-related data to optimize the display of images thereon. EDID information may include, for example, the specification of the attached monitor, the manufacturer's name, the display size, the pixel mapping data, the display product type, and the like.
Theoretically, computers should be able to interpret the EDID information to adjust the image as needed. However, the EDID information gathered from a television (connected via a DVI connector for example) may differ from the EDID information gathered from a computer monitor (connected via a VGA connector for example). In some cases, for example, the EDID information gathered from a television may not be in a format that is not readable by the computer. In other cases, the EDID information gathered for a television set may lack certain critical details needed to optimize the display of images thereon. Consequently, computers tend to have difficulties employing the EDID information gathered from television sets to adjust for the over-scanning that may have been performed by the television sets.
Analog connectors are uni-directional connectors (i.e., connectors that only transmit data from computers to monitors). Since no data about the monitor is transmitted back to the computer, the computer is unable to determine the monitor's display capabilities. Since both composite video and S-video connectors are analog connectors commonly used with television sets, some video graphic card manufacturers have modified their video cards to include built-in hardware to reduce the amount of over-scanning that may occur (e.g., by intentionally under-scanning the image to take into account the subsequent over-scanning by the television set). In many cases, however, the video cards may not be able to adjust for all of the over-scanning that may be performed by the television set. Thus, the image may still appear partially truncated when displayed on a television set.
The problem with over-scanning is further exacerbated when a computer is connected to a television using a component connector. Component connectors are connectors that enable the transmission of high-definition signal. As discussed herein, high-definition signals are signals that provide a higher resolution in comparison with analog signals currently employed for television broadcasts (USA as of 2005). High definition television signals, as the term is employed herein, represent signals associated with any of the competing and/or emerging HDTV protocols currently being proposed in the industry (USA as of 2005).
Component connectors are fairly new in comparison to the other types of analog connectors; thus, many video graphic card manufacturers have not fully modified their video cards to handle the over-scanning that may occur in television sets that may be connected to the computer systems via component connectors. When a television set is connected to a computer via a component connector, the computer may not, as a consequence, be able to compensate for over-scanning without user intervention.
When a computer is connected to a television set, a user may manually adjust the image for over-scanning by launching a display property panel and reconfiguring the video driver using the display property panel. However, few users have the knowledge or skill to perform this task. Further, since part of the image (such as the computer task bar) may have been truncated on the television screen due to over scanning, the user may have difficulties launching the program that will provide the display property panel.
Considering that a computer may not always be capable of identifying the type of monitor that is connected to the end of the connector, some computers may pre-set their video cards to automatically assume a specific type of monitor (i.e., either a computer monitor or a television set). However, the preset parameters employed for presetting the computer's video monitor may differ from the specifications of the television set or of the computer monitor actually connected to the computer. Accordingly, the image displayed may still contain a significant amount of distortion and/or may still be partially truncated. In some extreme cases, the computer's video display card may interpret the differences as an error condition. The result is a blank screen since the computer's display card may be configured to not display any image signal that may cause damage to the attached display device (e.g., monitor or television set).
Another method that may be implemented to correct for over-scanning involves the addition of a toggle switch, which allows a user to alternate between a television and a computer monitor mode. However, users who are reluctant to read instructions may be oblivious to the purpose of the toggle switch. Further, such an approach represents an inelegant solution to the problem and increases the hardware cost. Consequently, the toggle switch approach has not been widely adopted by manufacturers.